Various methods have been utilized for the identification of binding moieties capable of binding particular antigens. Prior art methods have been used to generate antibodies or antibody fragments, such as IgG, IgM, IgA, IgD, IgE, Fab, Fab′, F(ab′)2, Fd, Fv, Feb, scFv, or SMIP. Because these types of binding moieties have distinct properties, it is sometimes advantageous to convert a binding moiety of a first type into a binding moiety of a second type. Certain existing methods for the conversion of a polypeptide of a first type to a polypeptide of a second type can be inefficient. Thus, there exists a need in the art for compositions and methods for the efficient conversion of a polypeptide of a first type into a polypeptide of a second type (e.g., a chimeric polypeptide).